1. Field of the Invention
The present invention relates to an apparatus for producing baked products, especially sponge cake and a crepe for wrapping jam, cream, chocolate and the like.
2. Related Arts
A product having a good texture in elasticity, solubility in mouth, flexibility and other factors has been required for a baked products such as sponge cake and a crepe sheet.
Hitherto, various methods for producing the baked product have been proposed. For instance, such a method was proposed for improving quality of sponge cake in Examined Jap. Pat. Appln. Gazette No. 31 746/1969, wherein into a basic raw material containing wheat flour as a main component, a polysaccharide gum to be obtained by subjecting a starch or its decomposition product to fermentation is added in an amount of 0.1 to 2% based on wheat flour, or in addition thereto, a quality improving agent comprising 10 to 40 parts of a polyhydric alcohol or a starch decomposition product, 10 to 60 parts of a surface active agent, 1 to 5 parts of a synthetic or natural high molecular compound and 1 to 5 parts of a protein are added in an amount of 2 to 7% based on the wheat flour. Another method was proposed for producing a crepe sheet in Unexamined Jap. Pat. Appln. Gazette No. 74 945/1984, wherein wheat flour, eggs, oil or fat and water are added and mixed together to prepare a batter and then bake it to make the sheet.
While, for producing such a baked product, an apparatus was proposed in Examined Jap. Pat. Appln. Gazette No. 6 545/1975, which comprises a rotary drum, a heater incorporated in the rotary drum to heat an outer surface of the rotary drum to a predetermined temperature level by an electric heater, and a flat nozzle with a cooling member to supply a batter on the outer surface of the rotary drum for baking the batter to make it into a baked sheet-like product such as the sheet of crepe, omelet or spring roll.
In the method as disclosed in said Examined Jap. Pat. Appln. Gazette No. 31 746/1969, a polysaccharide gum is added to the basic raw material or in addition thereto, the quality improving agent containing as its main components, a polyhydric alcohol such as glycerine, methylcellulose and a surface active agent is added to delay staling and retrogradation of the product, but water-activity in the product is somewhat higher and thus a growth of bacteria can not sufficiently be inhibited. Therefore, the resulting product can not be stored over a long period of time. Further, mouth feeling gradually becomes worse due to the staling and retrogradation or oxidation of the product in the course of time. In the method as disclosed in said Unexamined Jap. Pat. Appln. Gazette No. 74 945/1984, a withstanding characteristics of mechanical folding is given to the product by adding xanthane gum to the basic raw material and setting a final moisture content of the baked product to a specific value of 40 to 45%, but an inhibition of bacteria growth has also not been attained and thus the product can not be stored over a long period of time. It is, therefore, similar to the former method.
According to the apparatus as disclosed in said Examined Jap. Pat. Appln. Gazette No. 6 545/1975, the heater per se is rotated together with the rotary drum. In such a structure, it is necessary to have a rotary transducer and a power supply device with a special slip ring which withstands a high electric power which is supplied to the heater. The thickness of the rotary drum should, of course, be made larger for accommodating or incorporating the heater therein to require much time for heating up the surface of the rotary drum to a desired level and this means that an expensive material having a high efficiency in thermal conductivity, such as copper should be selected for the rotary drum. Since the heater is embeded in the rotary drum, further, it is difficult to repair, when a heating wire is broken. Additionally it is difficult to attain uniform heating of the rotary drum, so that the entire outer surface thereof can not be served as the heating area, since the baking temperature of both sides thereof is relatively lower than the center area.